vault: upgrade the chart to 0.34.1, keep the server on 1.17.2

Chart 0.28.1 is only tested up to Kubernetes 1.30. 0.34.1 brings the
injector to vault-k8s 1.7.6. The server image is pinned to the running
1.17.2: the StatefulSet uses OnDelete, so nothing restarts now, but a
later pod restart would otherwise pull the chart's default and Shamir
unsealing needs the keys at hand for a Vault upgrade. Rendered with the
pin, the StatefulSet only changes in formatting and an extra check in the
config script that doesn't apply here.

vault/helm-vault.yaml

@@ -16,7 +16,7 @@ spec:
   sources:
     - chart: vault
       repoURL: https://helm.releases.hashicorp.com
-      targetRevision: 0.28.1
+      targetRevision: 0.34.1
       helm:
         valueFiles:
           - $values/vault/overrides.yaml

vault/overrides.yaml

@@ -4,6 +4,11 @@ global:
 injector:
    enabled: true
 server:
+   # Pinned to the running version: the chart would otherwise pull its own
+   # default on the next pod restart, and with Shamir unsealing a Vault
+   # upgrade needs someone with the unseal keys at hand.
+   image:
+      tag: "1.17.2"
    dataStorage:
       storageClass: longhorn
    standalone: